Can I take the volume of the primary tank into account when calculating secondary containment capacity?
Yes, the regulations state that the secondary containment system “must have a capacity of not less 110% of the container’s storage capacity”. The volume provided by the primary container can be taken into account where applicable. Most proprietary tank systems are designed so that the oil finds its own level in both containers if the primary container leaks. In this instance the primary container contributes to the total containment capacity. A similar position is achieved in a conventional bund where the tank is situated towards the bottom. However, you should take into account that such systems may only provide a 10% containment capacity in the event of overfilling. For example, a maximum volume delivery made to a tank more than 10% full will result in a loss of oil from the secondary container. The use of an overfill prevention device is good practice and you should consider these or other additional pollution prevention safeguards, such as additional containment capacity. Another i
